Message-ID: <1425091369.10337.69.camel@intel.com>
Subject: Re: [LKP] [mm] 3484b2de949: -46.2% aim7.jobs-per-min
From: Huang Ying <ying.huang@intel.com>
To: Mel Gorman <mgorman@suse.de>
Cc: LKP ML <lkp@01.org>, LKML <linux-kernel@vger.kernel.org>
Date: Sat, 28 Feb 2015 10:42:49 +0800
In-Reply-To: <1425090622.10337.67.camel@linux.intel.com>
References: <1425021696.10337.55.camel@linux.intel.com>
	 <20150228014642.GG3087@suse.de> <1425090622.10337.67.camel@linux.intel.com>
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On Sat, 2015-02-28 at 10:30 +0800, Huang Ying wrote:
> On Sat, 2015-02-28 at 01:46 +0000, Mel Gorman wrote:
> > On Fri, Feb 27, 2015 at 03:21:36PM +0800, Huang Ying wrote:
> > > FYI, we noticed the below changes on
> > > 
> > > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > > commit 3484b2de9499df23c4604a513b36f96326ae81ad ("mm: rearrange zone fields into read-only, page alloc, statistics and page reclaim lines")
> > > 
> > > The perf cpu-cycles for spinlock (zone->lock) increased a lot.  I suspect there are some cache ping-pong or false sharing.
> > > 
> > 
> > Are you sure about this result? I ran similar tests here and found that
> > there was a major regression introduced near there but it was commit
> > 05b843012335 ("mm: memcontrol: use root_mem_cgroup res_counter") that
> > cause the problem and it was later reverted.  On local tests on a 4-node
> > machine, commit 3484b2de9499df23c4604a513b36f96326ae81ad was within 1%
> > of the previous commit and well within the noise.
> 
> I have double checked the result before sending out.
> 
> Do you do the test with same kernel config and test case/parameters
> (aim7/page_test/load 6000)?

Or you can show your test case and parameters and I can try that too.

Best Regards,
Huang, Ying


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